Hinged tubular joint



4 Sheets-Sheet 1 Filed March 28, 1945 Dec. 11, 1951 G. MAXON, JR 2,578,364

HINGED TUBULAR JOINT Filed March 28, 1945 V 4 Sheets-Sheet 2 Dec. 11, 1951 GQMAXON, JR 2,578,364

' HINGED TUBULAR JOINT Filed March 28, 1945 I i 4 Sheets-Sheet 3 Patented Dec. 11, 1951 OFFICE HINGE'D TUBULAR JOINT Glenway Maxon, J r., Milwaukee, Wis.

Application March 28, 1945, Serial No. 585,233

2 Claims.

This invention relates to building materials and refers more particularly to structural building material in the form of comparatively light weight metal tubing helically deformed for strength and similar to that shown and described in Patent No. 2,294,240, issued to Adam F. Pollman, August 25, 1942.

This particular type of tubing has been proposed for scaffolding in the past in which use it is shown and described in the aforesaid Pollman patent, but it is one of the objects of this invention to render such tubing available not only for scaffolding but for trusses, frameworks of permanent and temporary nature such as shoring for tunnels, etc., and even for toys and models by the provision of special fittings and accessories for facilitating connection of lengths of such tubing in any of a wide variety of patterns.

Another object of this invention is to provide thin walled tubing of the character described with helical deformations defining internal and eX- ternal threads with the tubing having substantially uniform wall thickness throughout its length and available in a plurality of different diameters so related that tubes of difierent diameters may be threaded into one another to provide endwise adjustability of their combined lengths and/ or reinforcing.

With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate several complete examples of the physical embodiment of the invention constructed according to the best modes so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a perspective view showing the structural material of this invention assembled in a manner forming a series of trusses such as might be employed in a roof or an airplane hangar;

Figure 2 is an enlarged elevational view illustrating the manner in which the tubes are connected by accessory fittings to form the two right hand end panels of the trusses of Figure 1;

Figure 3 is an enlarged fragmentary detail view illustrating the connections between the upright, diagonal and lower chord members of the medial panels of the trusses with parts thereofv broken away and shown in section;

Figure 4 is a cross sectional view through Figure 3 taken on the plane of the line ti;

Figure 5 is a detail view partly in elevation and partly in section illustrating the use of a T-fitting formed of complementary sections;

Figure 6 is a cross sectional view taken through Figure 5-on the plane of the line 6 -6;

Figure 7 is a view of a slightly modified form of accessory fitting having its complementary sections hinged together and illustrating the manner of its use with the helically deformed tubing of this invention;

Figure 8 is a detail View partly in section showing still another modified form of accessory fitting by which laterals or braces may be connected with other lengths of helically deformed tubing at any point along its length;

Figures 9 and 10 are more or less diagrammatic views of single truss panels illustrating proper and improper methods of assembly respectively;

Figure 11 is an enlarged detail view of a single medial panel of the trusses shown in Figure 1 illustrating one manner of assembly thereof by which squareness of the panels is assured;

Figures 12 and 1B illustrate paneling for slightly modified types of trusses made with the structural material of this invention; and

Figure 14 is an elevational view of a piece of helically deformed tubing such as a coupling shown provided with lugs on its exterior to facilit-ate screwing the same into place on a length of tubing.

Referring now particularly to the accompanying drawings in which like numerals indicate like 7 parts, Figure 1 illustrates a series of connected trusses 5 forming a framework for aroof and which are conveniently constructed from the novel structural material of this invention.

The trusses illustrated constitute a representative showing of some of the many different assemblies possible to construct with the structural material of this invention and are believed to embrace most of the problems involved in joining the tubing into connected panelsof similar or I duplicate patterns or shapes.

3 forming the tubing in this manner are that the tubing retains a uniform wall thickness, and that substantially light weight tubing may be employed because of the increased rigidity for connections and also that the internal and external threads provided by the helical deformations permit reinforcement of the tubing by screwing one length of tubing inside the other wherever heavy loads are to be supported.

Hence, the tubing of this invention is preferably made in three diameters which may be conveniently designated S for standard, for oversize, and U for undersize (see Figure 3), and so related to each other as to enable screwing of a reinforcing tube either internally or externally on a standard size tube.

The threaded ends of the oversize and undersize tubin are also readily adjustably connectible with the standard tubing to form extensions and with a wide assortment of accessory fittings having similar externally and/or internally threaded portions to enable connection of lengths of tubing at different angles to each other and into framework of any design or pattern for permanent or temporary use.

As shown in Figure 1, the trusses 5 are supported on upright columns I of the helically deformed standard size tubes of this invention. These columns, as will be apparent, are preferably placed under the end panels of the trusses and unless the span is too great, the center or medial portions of the trusses remain unsupported.

The two end panels of the trusses are illustrated in detail in Figure 2 and each comprises top and bottom chord members 8 and 9 respectively, uprights H3 and diagonals ll all provided by lengths of standard size helically deformed tubing S of this invention.

A fittin l2 similar in shape to a T-fitting but provided with internal threads for cooperation with the adjacent helically deformed ends of the column 1, the chord 9 and the end upright l0 joins these elements together as shown in the lower right hand corner of the end truss panel in Figure 2.

The fitting I2 is shown in greater detail in Figures 3 and 4, and its internally threaded portions which receive the upper end of the column, the lower chord member 9 and the upright l0 areformed of oversized tubing 0 so that these members thread internally into the fitting. Medially between the top and side outlets of the fitting and which are disposed at an angle of 90 to one another, the fitting is provided with an angle branch I3 internally threaded and likewise of oversized tubing 0 so as to receive standard size tubing internally thereof.

The branch l3 provides for connection of the diagonal H across the rectangular panel defined by the top and bottom chords 8 and 9 and the adjacent uprights H0. The end upright l0 threadsinto the bottom of a special fitting I4, the left side outlet of which receives the right hand end of the upper chord member 8. The fitting I l has been shown in Figure 2 as an elbow-like fitting, but it will be necessary to use a fitting such as it with a straight run in line with the chord 8 for use at the opposite end of the truss. This results from the fact that the upper chord 8 at the opposite end of the truss is the last member to be assembled for completion of the truss and must be screwed into place from the left end of the truss.

The adjacent ends of the upper chord members 8 and the upper end of the center upright l0 thread into a fitting [5 with the chord 8 at right angles to the upright i9, and this fitting I5 is similar to the fitting l2 with the exception that it has two such angular branches Hi to receive the diagonals H at opposite sides of the center upright l0.

The bottom of the center upright I!) and the left hand end of the lower end chord 9 thread into a generally T-shaped fitting It to complete the perimeter for the end panel of the truss. It is to be understood, of course, that the fittings 12, M, 5 and it have one or more branches at their sides (perpendicular to the paper) as indicated in Figure 4 in the event a series of trusses are to be connected together as shown in Figure l by means of cross members 1?.

The connections [8 for the lower ends of the diagonals, as will appear from Figures 2 and 3, are different than that described in the connection of the chords and uprights to the various fittings. Referring now to Figures 2 and 3, it will be seen that the diagonals l l are of a length such that one of their ends (lower) clears the branch iii of the fitting I2 to which it is adapted to be connected. A substantially short nipple 26 of standard sized helically deformed tubing S is threaded into the interior of the branch [3 so that the outer end of the nipple lies closely adjacent to but is slightly spaced from the adjacent end of the diagonal ll. 1

This spacing between the nipple 2E) and the diagonal H permits threading or a helically deformed nipple 2| of size U, previously inserted into the lower end of the diagonal, outwardly thereof and into the interior of the nipple 20, so as to join the diagonal with the fitting portion !3 through the undersized internal nipple 2i and the standard size nipple 28.

In cases of moderate stress on the truss, the connection l8 thus far described will suffice for the diagonal but where a stronger joint is required between the diagonal and the fitting [2, a helically deformed coupling 22 of size 0 threaded onto the lower end of the diagonal before its assembly in the panel may be backed part way off the end of the diagonal and threaded over the end of the nipple 20 which protrudes from the branch l 3 of fitting l2. The coupling 22 not only reinforces the connection but also serves as a lock nut to prevent loosening of the connection when threaded up against the outer end of the branch I3.

The assembly of the two end panels shown in Figure 2 requires care and should be carried out as follows:

The fitting I2 is first threaded onto the top of the column 1'; the end upright Ii! is next threaded into the top of the fitting l2 until it meets the upper end of the column 7; the elbowlike fitting I4 is next threaded onto the top of the end upright It]; the upper chord 8 is next threaded into the side branch of the fitting It; the fitting l5 thereafter threaded onto the opposite end of the chord 8; a second post H3 is then threaded into the bottom of the fitting l5; both diagonals ll may then be threaded into the angularly disposed branch portions [3 of the fitting l5; the fitting H5 is next threaded onto the bottom of the second upright l6; and the bottom chord member 9 thereafter threaded through the fitting I 6 from the left-hand end thereof and into the side branch of the fitting I2.

The end panel is then completed with the exception of the connection l8 for the lower end of the diagonal, and this, of course, is accomplished in the manner previously described.

The second panel may be assembled in a similar manner by inserting an additional upper chord member 8 onto the left hand side of the fitting i5; screwing another fitting such as l2 onto the opposite end of the second chord 8; screwing a third upright l0 into the bottom of the fitting i2; threading another fitting such as it onto the lower end of the third upright It;

and then threading an additional chord mem ber it through the last mentioned fitting I2 from the left-hand end thereof and into the fitting it. The second diagonal l E is then joined to the last named fitting It by means of the connection it hereinbefore described.

Thus, it will be apparent that a truss may readily be constructed across an expanse for which it is designed, it being understood that the braces ii connecting adjacent trusses are all provided with connections such as I8 to enable tying together of the various trusses after the same have been assembled in their proper positions; and that the fittings on intermediate trusses have side branches at opposite sides thereof for connection of the braces IT.

in order to maintain accurate dimensions and to hold the various panels and naturally the entire truss in squared relationship, the proper lengths of tubing must be selected and the helical deformations providing the internal and external threads of the tubing and the fittings must be of uniform pitch and size.

Figures 9 and 10 illustrate the importance of using tubing of proper length and of threading the tubing a uniform distance into their accessory fittings.

Under proper conditions a panel such as that illustrated in Figure 9 results while if these prerequisites are ignored, the skewed panel shown in Figure 10 results. The panel of Figure 10 may be the result of using a diagonal of excessive length which would necessitate springing of the tubes adjacent to their connections with the accessory fittings as shown.

Figures 9, 10 and 11 indicate that the number of threads on the tubing, if of uniform size and pitch, can be used to aid the selection of the proper lengths of tubing to be employed in any particular type of paneling. The panels herein shown are composed of two classical 6-8-10 triangles having the diagonal as a common hypotenuse, so that the center to center distances of the fittings are multiples of 6-8 and I0. Hence, if the ends of the chords meet at the centers of their respective fittings, the number of threads on the chords 8 and S will be a multiple of 3.

As shown in Figure 11, it is preferable to provide the ends of the tubing with some means of indicating the proper depths that the tubing is to be threaded into its accessory fittings. As herein shown, the end portion of the tubing con stituting approximately the last three threads at which the center lines of the branches intersect, where the thread diameter is either at maximum or minimum so as to assure against the center to center distances of the panel members being other than an integral number of threads. Likewise, the distances from the centers of fittings to the outer ends of their branches must equal a whole number of threads, and referring to Figure 11, it will be seen that the run or" the fittings IZ which receives the ends of the chords must have exactly three threads at each side of the center of the fitting for a total of 6 threads; the branches receiving the uprights it preferably have a length such that the distance from the center of the fitting to the outer end of the branch is equal to 4 full threads; while the distance from the center of the fitting to the outer end of the diagonal branch 13 is preferably equal to 5 full threads.

It will be apparent, therefore, that in the Figure l1 example, the chords 8 and S! will have a length corresponding to 48 full threads; the up rights Hi will have .a length corresponding to 64 threads minus 2 threads or 62 full threads so that the uprights are 2 full threads shorter than the vertical center to the center distance between their fittings; while the diagonals will have a length corresponding to threads minus 11 threads for a total of 69 threads. This is assum ing that the ends of the uprights Hi thread into their respective fittings to Within one thread of the centers of the fittings, and that the upper ends of the diagonals are turned only 2 threads into their respective angle branches l3 to clear the ends of the uprights. The lower ends of the diagonals in this instance are spaced one thread away from the outer ends of the nipples 25 which protrude 2 full threads out of the angle branches i3. The ends of the chords, of course, meet inside the runs of the fittings l2 and are thus equal to the horizontal center distance between fittings.

Inasmuch as it is possible to construct the panel-like framework shown in Figure 2 eliminating the coupling joint l8, the diagonal for the panel may have a length corresponding to 80 threads minus 6 threads or a total of '74 threads. This results from the fact that the diagonal would have its opposite ends screwed into the diagonal branches l3 a distance corresponding only to the length of two full threads to enable the diagonal to clear the ends of the uprights.

While the paneling shown in Figures 2, 9, 10, and 11 is of a size andshape such that the panels are divided by the diagonals I I into pairs of right triangles the sides of which bear the relationship of 3, l, 5, numerous other triangle relationships may be used in such paneling wherein the three sides of the triangle have integer number lengths, and two such truss constructions are illustrated in Figures 12 and 13.

In Figure 12 an equilateral triangle truss structure is shown where the center to center distances between the fittings measured along the upper and lower chords and the diagonals is the same, the chords having an equal number of threads, and the diagonals havinga length2 threads less than the length of the chords since the diagonals in this case thread into the fittings in the same manner as the uprights ll) of the Figure 11 illustration. In this construction, it will be apparent that no splicing between the diagonals and the accessory fittings is necessary, the upper and lower chords being readily threaded lengthwise through their fittingsafter the'other members of each panel have been connected together. As

stated previously this type of assembly, that is, the lengthwise threading of the chords through their fittings to complete the respective panels, is also possible with the paneling shown in Figure 2, rendering the coupling joint l8 unnecessary in this instance.

The accessory fittings may be castings, forgings, pieces of helically deformed tubing welded together or stampings with the fittings made in complementary sections and welded or brazed together.

Referring to the fitting 12, as representative, illustrated in Figures 2 and 3, it is desirable for the sake of accuracy in the assembly of panels and the like that the straight run of such fittings be of sufficient length to accommodate the proper length of tubing threaded into opposite ends of the run. If the size of the tubing and the pitch of its threads is such as to require a three thread joint, the straight run of the fitting should have at least six full threads ending at substantially the same points on the circumference of the run at opposite ends of the fitting when the run is to act as a coupling between coaxial lengths of tubing.

Likewise, the stem should have a length such as to accommodate three threads of the tubing connecting therewith with the threads beginning on the outer ends of the branches at substantially the same points on their circumferences. ihe same is true of the branches i3, but as shown in Figure 11, these branches accommodate only 2 threads of the diagonal tubing or the coupling joint connected therewith. Accuracy of assembly is thus assured regardless of reversal or inversion of the fitting as will be necessary to accomplish the various connections for the paneling.

It should be remembered, however, the selection of the number of threads for the depth of the threaded connections between the tubing and the accessory fittings is optional, and that this depth may depend upon the diameter of the tubing to be used and the pitch of the threads formed on the tubing by the helical deformations thereof. In some instances it may be desirable to thread the tubing into accessory fittings for a depth of 5 or 6 threads, and for reinforcing the framework, whole lengths of tubing may 'be threaded into one another as indicated by the letter U in the lower chord 9 of Figure 3, or the tubing may be threaded part way into one another so as to afford endwise adjustability.

It is important to note that the fittings are so constructed that the center lines of the tubes threaded hereinto intersect at a common point. Maximum strength of the assembled structure is therefor assured.

In the assembly of framework for trusses or other structures, it frequently occurs that additional connections are required for bracing and the like. These braces must be attached to or extended from the assembled members of the framework.

Figures 5 and 6 illustrate one type of fitting by which the attachment of such bracing to an assembled framework or other structure may be readily effected. The fitting in Figures 5 and 6 is shown substantially as a T-fitting 3B which may be employed to connect the end of a supplementary member or brace iii of helically deformed tubing to the side of a similar length of helically deformed tubing 32 at an angle to the brace. The tube 32 may be considered as one of the main members of a truss or frame work.

The branches of the T fitting lie in a common plane and have internal screw threads for cooperation with the threads provided by the helical deformations on the tubing. The fitting, however, comprises complementary sections 34 stamped or cast or made in any other suitable manner and which are applicable to the tubing without requiring threading of the tubing thereinto.

As clearly shown in Figure 6 the fitting is illustrated as being split upon the plane passing through its branches and consequently the centers of the angularly disposed tubes with the complementary sections applied to the exterior of these tubes from opposite sides thereof. One or more branches or collars of the fitting which embrace the tubes may be tightly secured about the tubing received therein by means of a helically deformed coupling 35 threaded over the complementary sections of the collar as shown.

The use of fittings made in complementary sections precludes the necessity of cutting lengths of tubing already assembled into panels in order to threadedly connect additional tubing angularly with respect thereto for bracing or other purposes.

The same principle is employed in the construction of the modified type of fitting shown in Figure I wherein the complementary sections of the T-fitting are hinged together as at 36 along their adjacent edges remote from the stem portions 31 of the fitting which are to engage over the exterior of the one end of the brace 3|.

The hinge 35 thus holds the complementary sections 3 in their proper relationship so that the threads of the fitting accurately engage the threads of the tubing upon closing of the hinged sections about the tubing. A coupling 35 slipped over the end of the brace 3| before application of the hinged fitting thereto likewise threads over the split collar or branch sections 3'! to securely clamp the sections 34 of the fitting onto the tubes 3| and 32.

If desired, a T-fitting similarly to that shown r in Figure '7 and having hingedly connected complementary sections may be provided with trunnions 38 at opposite sides thereof lying on a common axis perpendicular to the plane passing through the axes of the tubing to be connected, as shown in Figure 8.

In this case the collar or stem portions 39 are not integral with the fitting, but are connected thereto by arms 4i! extended from the sides of the collar sections 39 to overlie the sides of the main branch or collar sections M for pivotal connection with the trunnions as at 62. In this instance also, a coupling 35 threaded over the collar sections 39 serves to lock the fitting in place pivotally connecting the brace with the tubing.

It will be obvious to those skilled in the art that the split fittings may have any desired number of branches either perpendicular to a straight run of the fitting or at an angle other than thereto and may be connected to the main members of a framework at any point along their length; and that the trunnion type fitting conveniently provides for the attachment of braces at any desired angle to the tubing upon which the fitting i applied. These trunnions, as will be readily apparent, may be incorporated on any or all of the fittings l2, i l, l5 or IE, thereby providing for attachment of wire braces Whenever necessary and affording means engageable by a spanner type wrench for turning the fittings into place on the tube ends.

In the embodiment of the invention illustrated in Figure 14, a piece of helically deformed tubing 45 is shown provided with lugs or studs 46 welded to the exterior of the tubing and spaced at substantially 90 intervals about the circumference of the tube. These lugs facilitate screwing together of the tubing during assembly inasmuch as they enable a spanner-type wrench to be applied thereto thus eliminating the necessity for pipe wrenches.

The lugs 46 are preferably formed of round cross section stock so that they can also be used as trunnions for pivotally connecting braces and the like thereto by means of split collar sections 39 and couplings 35 a previously described. When used in this latter sense, the tube 45 would be in the nature of a coupling threaded over another piece of helically deformed tubing.

At the middle portions of roof and bridge trusses and other frameworks subjected to great compressive and tensile stresses, reinforcement is provided by the simple expedient of threading either an undersized or oversized length of tubing into or over the standard size tubing at these areas. In fact, all members under excessive compression or tension stresses may be strengthened from either the outside or the inside or both by the different diameter tubes of this invention.

From the foregoing description taken in connection with the accompanying drawings, it will be readily apparent to those skilled in the art that the structural material of this invention for the first time enables metal framework to be fabricated in the field in a simple and efficient manner to produce an exceedingly strong and light weight structural unit for permanent or temporary use; and that because of the fact at least the engaging portions of the fittings and tubes have helical deformations providing screw threads both internally and externally and have uniform wall thick ness stress concentrations at the points at which the tubes emerge from the fittings are unusually low. This results from the fact that the fittings have the ability to stretch along with the tubing when bending or torsional forces are applied to the tubing. In other words, there is no sudden change in strain such as occurs at the points at which regular pipe emerges from standard pipe fittings and which usually results in breakage at said points by reason of high stress concentrations.

What I claim as my invention is:

1. In a structure of the character described: main and secondary members disposed at an angle to one another with the end of the secondary member adjacent to the side of the main member and their axes intersecting, said members placement, arm on one of said collars disposed at opposite sides of said plane passing through the axes of the members and having their ends overlying the opposite sides of the other of said collars, and a pivotal connection between the end portions of said arms and said other collar for pivotally connecting said collars.

2. An accessory fitting for structural material of the character described, comprising: a collar having helical deformations on its interior; a plurality of circumferentially spaced studs fixed to the collar and projecting from its exterior, at least two of said studs lying on a common axis normal to the axis or the collar; a second collar; and means on said second collar cooperating with said two studs to pivotally connect the collars with the axis of the second collar intersecting the axis of the first designated collar, said second collar likewise having helical deformations at least on its interior surfaces to provide screw threads.

GLENWAY MAXON, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 182,203 southward Apr. 20, 1875 359,749 Tourgee Mar. 22, 1887 366,771 Gould July 19, 1887 610,262 Dikeman Sept. 6, 1898 611,588 Brooks Sept. 27, 1898 824,501 Molloy June 26, 1906 824,502 Molloy June 26, 1906 1,180,157 Lacey Apr. 18, 1916 1,281,883 Toof Oct. 15, 1918 1,445,234 Palmer Feb. 13, 1923 1,554,224 McGrath Sept. 22, 1925 1,827,086 Hunter Oct. 13, 1931 2,211,283 Mercer Aug. 13, 1940 2,233,901 Scacchetti Mar. 4, 1941 2,284,898 Hartman June 2, 1942 2,294,240 Pollman "Aug. 25, 1942 

